Time-delay relay



OGL 2, 1962 w. c. BRoEKHuYsEN 3,056,871

TIME-DELAY RELAY Filed Sept. 22, 1958 4 SheetS-Sheet 1 INVENTOR.

WILLIAM C. BROEKHUYSEN ATTORNEYS 06t- 2, 1962 w. c. BROEKHUYSEN3,056,871

TIME-DELAY RELAY Filed Sept. 22, 1958 4 Sheets-Sheet 2 1NVE1\1TOR.

WILLIAM c. BRoEKHuYsEN Mme, nu( X/ML l* ATTORNEYS Oct. 2, 1962 w. c.BRoEKHuYsEN 3,056,871

TIME-DELAY RELAY @l INVENTOR.

WILLIAM C. BROEKHUYSEN ATTORNEYS Oct 2, 1.962 w. c BRol-:KHuYsl-:N3,056,871

TIME-DELAY RELAY Filed Sept. 22, 1958 4 Sheets-Sheet '4 F/G. /4 F/G. /5

2a` mi as 44 i?, f3; 5 i6 zo INVENTOR.

WILLIAM. C. BROEKHUYSEN BY wg, [DJ @JX/nun ATTORNEYS United StatesPatent C) f G-V Controls Inc., East Grange, NJ., a corporation of NewJersey Filed Sept. 22, 1958, Ser. No. 762,349 23 Claims. (Cl. Zim-122)This invention relates to a functionally .and structurally improvedelectrothermal relay involving a time-delay factor.

By means of the present teachings a unit is provided which may besubjected to a wide range of forces and conditions without impairing itsfunctioning, and which will embody a response of high accuracy.Accordingly, the unit may be included in `a missile to control thefunctioning of the latter under the extremes of conditions encountered.in its operation.

The relay will be designed to occupy only a minimum of space, and willembody a relatively simple structure embracing few components, connectedto each other to furnish a unit of high accuracy and the performance ofwhich may be relied upon even when the unit is subjected to extremes ofacceleration yand temperature; the relay embodying an adequate timingrange.

With these and other objects in mind, reference is had to the attachedsheets of drawings illustrating practical embodiments of the inventionand in which:

FIG. l is a bottom perspective view of the exterior of the relay casing;

FIG. Z is a plan view of the relay `assembly with the cover removed;

FIGS. 3 and 4 are sectional side views taken respectively along thelines 3-3 and 4-4 in the direction of the arrows as indicated in FIG. 2;

FIGS. 5 and 6 are transverse sectional views taken along the lines 5 5`and 6-6 respectively in the direction of the arrows as also indicatedin FIG. 2, with the cover in position;

FIG. 7 is a transverse sectional view in enlarged scale taken along theline 7-7 in the direction of the arrows as indicated in FIG. 3;

FIG. 8 is a sectional view taken along the line 8--8 in the direction ofthe .arrows as indicated in FIG. 7;

FIG. 9 is a perspective view of the main operating mechanism of therelay;

FIG. 10 is a view similar to alternative form of structure;

FIG. 11 is a transverse sectional view taken along the line 11-11 in thedirection in FIG. 10; and

FIGS. 12 to 16 inclusive .are diagrammatic representations ofalternative forms of relay mechanisms illustrative of the principlesembodied in the design present in the instant application.

The missile time-delay relay embodied in the present teachings isdesigned to have a minimum response to vibrations up to 2000 cycles persecond, even where a force in excess of twenty times gravity isinvolved. Additionally, it will be highly resistant to shocks vin excessof 50 g with `a duration of as much as 11 milliseconds, and will involvea minimum departure in timing where unidirectional forces as high as 50g are encountered. Moreover, ambient temperature compensation will bepresent, ranging, for example, from minus 65 C. to plus 125 or evenbeyond. High accuracy, involving narrow setting tolerance and goodrepeatability, will be achieved, .aside from the fact that there will beminimum sensitivity of the unit regardless of its position. The timingrange which may be embraced will be adequate, and the time setting maybe adjustable. The adjusting means will FIG. 7, but showing an of thearrows as indicated A 3,056,871 'Patented oct. 2, 1952 ice convenientlybe structurally independent of the enclosure.

Hereinafter reference will be made to tapered design. By this is meantthat the weight of moving parts should decrease very rapidly as themotion is multiplied. In fact, the mass of the motion-multiplyingmechanism should change far more rapidly than inversely proportional tothe ratio of multiplication. By the present teachings, such a tapereddesign is achieved.

As is well understood, in the case of a high ratio lever (10:1 orhigher) it is almost impossible to design that lever and its mounting ina manner such that it will be so rigid as to have a natural period ofvibration above 2000 cycles per second. However, an isoscelestriangleeven a very low one-when firmly supported at the two ends of itsbase, will still be very rigid at its apex. This is because its sidesare under compressive or tensile stresses, rather than under bendingstresses. However, the ratio of multiplication that can be obtained withsuch a triangular design and with the actuating member as its base ispractically limited to 3:1 or 4: 1. For substantial contact motionwithout high energy input and excessive temperature rise of theactuating member, a multiplication of at least 10:1 is needed. Toachieve this end result requires two multipliers in cascade, i.e.,connected in such manner that the over-all multiplication is the productof the multiplication ratios of the two.

Reference is had primarily to FIGS, 12 to 16 inclusive diagrammaticallyillustrating structures involving multiple motion-magnifying ormultiplying mechanisms arranged in cascade. In FIG. 12 the numeral 20indicates supporting portions providing points of reference. Thisstructure may be included in the frame of the mechanism. Themotion-multiplying mechanisms are of the V type. The iirst of themembraces .a base 21 with which a heater in the form of a resistance wire22 is associated. Connected to the ends of the base and to each other,are sides or arms 23 which furnish at their juncture the apex of the V.A link 24 is interposed between the point of connection of base 21 andone of the arms 23 and the adjacent surface of the supporting frame. Theconnections between the several elements may be regarded as pivotal,although in actual practice a flexible coupling zone or part willordinarily be present. It will be understood that with a design of thistype, and in response to the application of heat to base 21, amultiplication ratio of up to, for example, 4:1 may be obtained at theapex of the V.

The second motion-multiplying mechanism involves a different V design.It will include arms 25 and 26 disposed at an acute angle with respectto each other, with a ratio of height to base of approximately 4:1. Acontact 27 is suitably secured adjacent the apex of the V. This contactcooperates with a second contact 28 suitably mounted by frame 20 or anyother proper fixed point. The leg or arm 25 is connected in any desiredmanner adjacent the apex of the V delined by arms 23. The second arm 26,connected to arm 25, is in turn connected to a suitable fixed point ofreference, such as the frame 2i). In the diagram, for the sake ofclarity, leg 26 is shown shorter than leg 25, but in actual design theselegs are made as nearly equal in length as possible.

Otherwise stated, the second V is of a different nature than the rstassembly. It resembles in certain respects a cantilever, of which leg 25is the long arm; the distance between the ends of V26 and 25 being theshort arm. The ratio of these distances is only 3:1 to 4:1, therebyavoiding low resonance. Its legs are more under compression or tensionthan bending. In that respect it does yagree with the inst-mentioned Vand for this reason can be considered as a closed structure.

With a construction of this type an assembly is furnished which will berigid enough to give an over-al1 natural frequency of vibration of morethan 2000 c.p.s., and one which will also furnish a motion rangeadequate for relay purposes. The resonance frequency remainssubstantially constant from one extreme position to the other. The Vembracing arms 23 will be most responsive to vibration along axis X,lbut substantially nonresponsive to vibration along axis Y. The Vembracing arms 25 and 26 will be more responsive to vibration along theY axis. Accordingly, maximum sensitivity to external vibration isreduced.

It is feasible to arrange the second stage lever of the cascade parallelto the first stage. This has been illustrated in FIG. 13, in which thereference numerals to 24 inclusive designate similar or identical partsto those heretofore described. Additionally, in this view it will beobserved that the second multiplier includes a link 29 connected to theshort arm of a lever 30 pivotally supported as at 31. The outer end ofthis lever mounts a contact 32 for cooperation with a contact 33. Theforces generated by the two mechanisms incident to vibration along theaxis X will oppose each other in the connecting link Z9. In theory, thiscould reduce the over-all response to zero. However, to achieve this theforces would have to be equal and 180 out of phase.

As shown in FIG. 14, the motion-multiplying mechanisms may include whatmight be termed two flat Vs 33 and 34', the parts of which are flexiblyor rockingly connected at points such as 35. A heater element 36 isassociated with the base or actuating member 34 and serves to controlthe functioning of the relay. Arms 37 carrying cooperating contacts aremounted in line with, or adjacent the apex of each of assemblies 34 and33. The relative motion between these contacts is the expansion of theactuating member multiplied by the sum of the multiplications of the twomechanisms, rather than by their product. As far as vibration responseis concerned, mechanisms constructed along the lines indicated in FIG.

14 will have characteristics similar to those of theV mechanismtraversed in FIG. 13.

Employing a structure embodying the design of FIG. 12, a rst resonantfrequency at the contact 27 as high as 2000 c.p.s. has been obtained;the gap between the contacts being .015" for normal time settings. Witha view to suppressing this first resonance point, it is feasible toresort to the structure schematically shown in FIG. l5. In that view therst motion-multiplying mechanism includes a pair of generally L-shapedarms 38 pivotally or flexibly connected to each other to provide anVapex portion, and similarly connected at their outer lower ends to abase member 39. The latter has the usual heating element 40 associatedwith it. Thus, a at'V structure similar to one of the units of FIG. 14is provided. In common with the assemblies of preceding and succeedingfigures, an isoceles triangle arrangement is present. Similarly to thestructures shown in FIGS. 12, 13 and 14, a link 41 connects one end ofthe b-ase l to have capabilities of controlled movements with respect tothe supporting frame 20 or its equivalent. The second motion-multiplyingmechanism is preferably identical with that shown in FIG. 12 andincludes a pair of arms 42, one of which is flexibly or pivotallyconnected adjacent the apex of the arms 33, with the second arm 42similarly connected to frame 20. A contact 43 is disposed adjacent theapex of this second mechanism and cooperates with a contact 44 carriedby the frame 20. Also supported by the frame or a fixed point ofreference is a light spring 45 extending at a substantial angle to thearms of the second motion-multiplying mechanism. This spring supports asemi-spherical projection or ball point 46 bearing against the secondarm 42. Due to the disposition of the parts with respect to each other,a pivotal motion of the second multiplying mechanism will cause arubbing action or friction between the arms carrying contact 43 and thebearing surface 46. This friction prevents the vibration at contact 43from building up to a substantial amplitude at or near the resonantfrequency. The lower the mass of the sec-V ond multiplying mechanismembracing the arms 42, the

less pressure will be required between these arms and bearing surface46. With this pressure being of low value, the resultant friction doesnot interfere with the normal motion of the contact body 43 incident tothe expansion and contraction of the base member 39. However, it isadequate to reduce the response to vibration at this rst resonantfrequency to a negligible factor.

As a result of tests, it was discovered that no matter how rigid thestructure involved, the timing of thermal relays generally tends toincrease under the influence of unidirectional acceleration. Theincrease varies with the direction of the acceleration force relative tothe relay. Only rarely does the timing decrease or remain constant. Thedecrease is never very large, but the increase can be in excess of Thisis to be attributed not so much to the mechanical effect oftheaccelerating force, but rather to the increase in thermal convectioncurrents inside the relay enclosure. These increased thermal currentsincrease thermal coupling between the actuating and compensatingmembers. This is substantiated by the fact that if the relay isevacuated, the eifect of unidirectional acceleration is Vgreatly reducedand becomes negative when lthe direction is such that mechanicalcompliance would lead one to expect a decrease. In a well-designedstructure this mechanical compliance can be reduced to a negligiblefactor.

However, as a practical matter, evacuation is not the simplest and mosteffective way to eliminate acceleration sensitivity. Even a small amountof leakage has a pronounced effect on the operation of a relay which was`originally adjusted in a substantially complete vacuum.

This small leakage can affect the relay to an extent such as to renderit inoperative. Therefore, the reliability of the unit is reduced.However, by disposing a partition or baille as at 47 within what mightbe termed the enclosed structure, an effective coupling by convectioncurrents is prevented between the actuating and compensating members ofan assembly. The result obtained by such a structure is almost aseffective as with a substantially complete vacuum, without Igiving riseto the objections inherent to the use of a vacuum. With the arms beingof L-shape, they provide the necessary clearance for the baille, witheach arm remaining rigid. Position or orientation sensitivity is simplyanother manifestation of the effect of convection currents on a smallerscale. It is also effectively eliminated by the use of a baflle orpartition,V such as 47.

The heaters 22 36 and 40, heretofore referred to, may be enclosed inmembers 21 or 39 in a manner corresponding to the disclosure of my priorPatent No. 2,700,084 of January 18, 1955. Where it is desired'to havetime delays shorter than are achievable by such a member, an externallyheated thin strip or ribbon maybe employed. However, it then becomesnecessary to keep this ribbon under tension at all times. This could beachieved by increasing the pressure of spring 45, as in FIG. 15. Suchincrease would result in a substantial increase in the friction betweenthe bearing surface 46 and the arms 42 to a degree which would probablyaifect the timing accuracy of the relay. Therefore, it is better to useseparate springs for biasing and damping. This has been showndiagrammatically in FIG. 16.

In that view, and similarly to FIG. 15, a pair of L- shaped arms 48 areprovided which are rockingly connected to each other and to a base 49.With the latter, a heater 50 is suitably associated. A baffle or barrier51, corresponding to unit 47, is disposed within the space between thesearms and base 49. Connected to a point adjacent the apex or coupling ofarms 48 is the second motion-multiplying mechanism 52, carrying acontact, This mechanism may be in all respects similar to the mechanismheretofore described in FIG. 15. Its contact u is engageable with acontact S3, and a spring 54 carrying a suitable bearing surfacecooperates with this second mechanism in a manner similar to parts 45and 46 in FIG. 15.

Additionally, springs 55, conveniently presenting spherical orsemispherical bearing surfaces at their free ends, are mounted by thesupporting structure 211 and engage the arms 48 providing the V atopposite points beyond its apex. The motion at the outer end of springs'5 is extremely small and occurs incident to the expansion andcontraction of the actuating member or base 49. Moreover, springs 55 areplaced as nearly parallel to members 43 las is feasible, therebyreducing the relative motion between the tips of springs 55 and members48 to a minimum. Accordingly, friction at these points is minimized andhas negligible effects on the timing accuracy, despite the fact that thepressure of the springs on members 48 may be substantial. It will beunderstood that while spring 54 is primarily provided to produce adamping effect, it does contribute to a small degree toward tensioningthe parts. Also, while springs 55 are provided mainly for the purpose oftensioning, they may exert a slight damping effect.

In this assembly and with the use of a ribbon-type base, this actuatingelement is likely to have a resonance point below 2000 c.p.s. While thiswill cause negligible motion at the contact carried by arms 52, it couldresult in fatigue failure of the ri-bbon, the heater-connecting leads,etc. This resonance point is conveniently suppressed by the use of alight damping spring 56 carrying a suitable bearing engaging the centerof base element 49. An insulating strip 57 is desirably interposedbetween the heater winding and spring 56.

Thus, in each of the designs shown in FIGS. 12, l5 and 16 there isprovided a pair of motion-multiplying mechanisms connected to each otherin cascade. The primary mechanism involves rockingly connected andrelatively rigid members, of which one provides a base element. Thatelement, when exposed to heat, will expand, carrying with it theadjacent ends of the members connected therewith. Those members providea central or apex portion to which there is imparted movement of amagnitude substantially greater than the expansive movement of the baseelement. That element has one end fixedly connected to` a supportingframe. The opposite end of the element is movably connected to theframe, preferably by a link, so that its movements are controlled.

The secondary motion-multiplying mechanism involves a pair of rockinglyconnected members, one of which is coupled for movement with the centralor apex portion of the rst mechanism. The other member of that secondarymechanism is conveniently rockingly connected to the base, as in FIGS.l2, and 16. This will result in the central zone of connection of themembers of that secondary mechanism having movement which will begreatly magnied over the movement of the central or apex portion of thefirst mechanism.

To this zone there is connected a contact engageable with a secondcontact to control the circuit. It is a preferred concept of theinvention to have the mass of the mechanisms decreasing from the baseelement through to the part of the second mechanism which has maximummovement and to which is connected the controlling contact. Also, it ispreferred to have the axes of maximum sensitivity to shock and vibrationof the mechanisms at substantially right angles to each other, so as tominimize these factors.

Moreover, it is in many instances preferred to resort to a dampingac-tion effective over the complete range of vibration to which the unitis subjected. This action will, according to the present disclosures,not induce a failure of the assembly. Also, it will in no manner affectsensitivity of control of the relay. In this manner, a unit is providedwhich will operate with entire satisfaction even when exposed to highfrequency vibration.

The relays will be enclosed, and this enclosure conveniently providesthe aforementioned supporting frame. The thermal convection currents arepreferably deected in their flow, so that they cannot link the base andcompensating members directly when the relay is subjected to varyingamounts of unidirectional acceleration.

A practical embodiment of the structure shown in FIG. l5 is illustratedin FIGS. 1 to 8 inclusive. Referring primarily to FIG. l, a suitabletype of casing has been shown at 58, which may have any desired outlineand which may be closed by a cover S9. Supporting brackets or footportions 60 are preferably integral with that casing and may receivesecuring elements (not shown). Within the casing two multiplyingmechanisms arranged in cascade are disposed. As indicated in FIGS. l2 to16 inclusive, the weight of the moving parts decreases rapidly as themotion is multiplied.

Thus, referring to FIG. 2, the numeral 61 indicates the electricallyheated actuating or base member of the initial assembly, to whichcurrent is supplied through leads 62. As shown in FIG. l, these may becontinued exteriorly of the casing, in the form of terminals 63. Theactuating member conveniently has a construction similar to thatdisclosed in my afore-mentioned patent, and is preferably made of amaterial with a high coefficient of expansion, such as stainless steel.

A channel member 64 has L-shaped brackets 65 secured to its ends by, forexample, spot welding. Actuating member 61 is supported on brackets 65by two flat spring members 66, also convenien-tly by spot welding. Theflanges of one of the brackets 65 are secured, for example, again byspot welding, to one end of a wide fiat spring 67. This may be similarlyattached tol a boss or supporting portion 68 extending from the innerface of the casing. A spring 69, similar to spring 67, is secured at oneend to the second bracket 65 and at its opposite end is secured to abracket 70 projecting from the inner face of casing 58. A channel-shapedsupporting plate 71 is attached to the underside of bracket 70. Anextension of the adjacent spring 66 passes through slots in the spring69 and plate 71 and is attached to a flange 71' extending outwardly fromthe surface of supporting plate 71. Accordingly, springs 66 and 69furnish for the adjacent bracket 65 a crossed-spring pivot.

The `side flanges of channel member 64 are reduced in height toward thecenter of that member. Adjacent that center zone `they are completelyeliminated to provide a notch portion, as indicated at 72. In linetherewith, the base of channel 64 is preferably formed with an opening.Accordingly, there is created yat this point a Zone of flexure orswinging connection such that the two end sections of the channel member64 may rock with respect to each other. To one side of this zone the webof the channel is pierced so as to receive la pin 73. Insulation isinterposed between this pin and the adjacent edges of the channel memberto electrically -isolate pin 73 from the channel member. Conveniently,the structure of the insulating layer comprises a glass bead 74, which,as shown in FIG. 7, is supported by an eyelet 75. It is thus apparentthat as the primary motion-multiplying mechanism of the relay functions,pin 73 will be moved `along its axis.

It should be noted, however, that as long as base member 61, channelmember 64 yand brackets 65 are made of the same material, or ofmaterials having the same coefficient of thermal expansion, any changein ambient temperature causing an equal change in temperature of theseparts will not cause any axial motion of pin 73. The ambient expansionof member 64 and brackets 65 cornpensates for the ambient expansion ofbase member 61.

Extending parallel to and spaced outwardly from channel 64 is a channelmember 76. The latter is maintained in position by having one of itsends secured to spring 67 at a point intermediate the attachment of thelatter to bracket 65 and support 68. The opposite end of member 76extends adjacent a corner bracket 77 and 4is connected to the latter bymeans of a flat spring 78. That spring extends through a slot Yin member71, to the outer end of which channel 76 is rigidly connected.

As shown lto best advantage in FIGS. 3, 7 and S, the web of channelmember 76 is pierced at four points and provided with eyelets 79, whichpreferably receive insulating bodies in the form of gl-ass beads 80, inturn mounting pins S1, 82, 83 and 84. A T-shaped bracket 85 issupporte-d between pins 81 land 82 adjacent one side of channel member76. A strip 86 is supported between pins 83 and S4 adjacent the oppositeside face of the channel. This strip carries a contact 87 at apreferably central point.

Still referring primarily to FIGS. 7 and 8, a flat spring 88, bent intoa sharp V to provide a proper unit or assembly, supports adjacent itsapex portion a contact S9 in line with contact 87. 4One leg of thisspring is attached to bracket 85, and the opposite end of the same issecured t-o pin 73. VA small V-shaped piece 88 is preferably insertedbetween and attached to lthe legs of the spring assembly 88 near itstip. The purpose of this inner V is to strengthen the tip Zone of thespring 88 and to provide a path by which the heat, generated in the zoneof the contacts 87 and 89 under heavy cur-rent load, can be distributedover both the legs of assembly 8S. This will prevent unequal expansionof these legs as a result of this heat. As is apparent, uneven expansionmight otherwise interfere with the proper operation of the relay.

The body of spring 88 extends through an opening 90 inthe base or web ofchannel member 76. Also extend-v ing through this opening is a leaf orspring strip 91. The inner end of the latter is secured to the upwardlybent shank or leg of bracket 85. Its opposite end carries a bearingmember 92, having a spherical contour, which engages the rear surface ofthe spring assembly S8. With a view to adjusting the position of contact87, a friction nut 92 is att-ached to the inside of channel 76 oppositecontact 87, and the flange of channel 76 is provided with an opening inline with the nut. Into this nut is inserted a screw 93 convenientlyformed with a glass tip in engagement with lthe rear face of strip 86.It is apparent that in this manner, strip 86 may be flexed, so thatcontact 87 assumes a properly adjusted position.

As afore brought out, leads 63 conveniently extend through the base ofthe casing and connect wires 62 with the coil Iof actuator 61.Similarly, leads 9d are fused into and insulated from the casing,preferably by glass beads. These leads extend into the body of thecasing, and one of them is connected to the end of pin 82. The other isconnected to `one of the pins 83 and 84. A tube 95 is sealed preferablyto the base of the casing and disposed in line with screw 93.Accordingly, :after the assembly is completed, it can be tested andadjusted by inserting a screwdriver through the bore of the tube andturning the screw. After the adjustment has been perfected, air may beexhausted through this same tube. Thereafter, and again using the tube,the casing may be filled with a suitable gas, if desired. Otherwise itmay be left under vacuum. In any event, the tube is finally pinched offand sealed, in accordance with conventional practice.

A shield 96 in the form of a plate is mounted centrally betweenactuating member 61 and the compensating assembly. It is preferably madeof a material, such as mica, with low heat conductivity and high opacityfor heat radiation. A metal shield may also be used, if desired. In anyevent, the unit is supported between brackets 97 and 98 secured to thecasing and cover respectively. This shield acts as a barrier to preventa change in thermal coupling by convection currents, between the severalparts, when current is supplied through wires 62 to operate theactuating member, while the entire relay is subjected to highunidirectional acceleration. As illustrated, the shield extends betweenbrackets 65 through the entire height of the casing and serves toprevent the build-up of strong 3 convection currents under the inuence4of such high unidirectional acceleration. l

Considering the operation of the assembly as heretofore described inconnection with FIGS. l to 8 inclusive, it will be understood that withcurrent supplied through leads 63, the heater element of the actuatingmember 61 will be energized. Accordingly, the latter will expandlongitudinally and cause Ithe center `of the compensatingV member, asdefined by channel element 64 to move toward the actuating member,incident to a flexing action. Accordingly, pin 73 will exert a thrust onthe spring or assembly 68. Such force acting on the leg of theassembly'adjacent 4strip 86, it follows that contact 89 will be shiftedtoward contact 87 to a point where they finally engage. Therefore, thecircuit between pins or leads 94 will be closed, in that a completecurrent path will be furnished via one of these pins through pin 82,bracket S5, spring assembly 88, contacts 89 and 87, strip or bracket 86and pin S4 to the second lead or pin 94. The time delay between theapplication of power to pins 63 and the closing of the circuit dependsmainly on the watts input to the actuating member 61, the thermalcapacity of the mass :of the actuating member and the initial gapbetween contacts 87 `and 89.

The application of power may be continued beyond the time of contactclosure. The parts will ordinarily be designed so that they have a rangeof movement beyond the minimum lrequired to hold contacts 87 and 89 inclosed positions. Therefore, with the contacts engaged, furtherexpansion of the actuating member will cause pressure between thosecontacts 4to build up. This will create elastic stresses in thestructure. Due -t-he extremely low weight of spring assembly or unit 88,ths'elernent and its supporting structure (including also channel member64) can be made sufficiently flexible to keep these stresses within theelastic limit `of the material, and yet be sufficiently rigid to preventmechanical resonance below 2000 c.p.s. When power to pins 63 is removed,the contacts will continue to remain closed until the actuating memberhas cooled and its length has been reduced to ia point where thestresses are reduced to Zero. In this connection, it will of course beunderstood that the several parts of the assembly are convenientlyformed of the same metal, so that variations in ambient temperature Willnot result in differentials of expan-sion between the components of theassembly.

A comparison of FIGS. 7 and l3 shows that the direction of contactmotion in the first figure is along axis Z, while in FIG. l5 itis alongaxis Y (see FIG. l2). However, since both these axes are at right anglesto the axis X (FIG. 2), it will be clear -that the maximum sensitivityto vibration is reduced because the V defined by member 64 will be mostresponsive to vibration along axis X, but substantially non-responsiveto vibration along axis Z. The V embracing member S8 will be moreresponsive to vibration along axis Z.

The entire opera-ting mechanism is supported in the casing at only threepoints, involving brackets or members 68, 70 and 77. Only the bracket 70is rigid in all directions. The support on bracket 77 through spring 78is rigid in directions Y and Z, but permits expansion and contraction ofbracket 70 and plate 71 independently of the shell or casing 58, andvice versa. The support on boss or bracket 68 through spring 67 is rigidin directions X and Z, but permits expansion of all parts of theassembly along the axis Y. It also permits of a slight pivoting motionof bracket 65 connected to spring 67, 'as well as the adjacent end ofchannel member 64. Thisv will be under the influence of the expansionforce exerted by actuating member 61. Springs 66 and 69 allow a similarpivoting motion of the bracket 65, to which they are connected, and ofthe base portion of channel member 64 attached to this bracket.

From the foregoing, it is apparent that actuating member 61, whichinvolves the heaviest component of lthe assembly, is rigidly supportedin all three axes, conceding that supporting plate 71 is rigid. Itsright-hand end is restrained from movement along its axis by spring 66,and from movement at right angles to the axis, in the plane of thedrawing, by spring 69. Movement of this end at right angles to the planeof the drawing is prevented by the fact that spring 69 is of substantialWidth.

Spring 67 being also of subst-antial width, the left end of base member61 is restrained from movement at right angles to its axis both in theplane of the drawing and at right angles to it. It is, however, free tomove along its axis when member 61 expands or contracts as a result ofchanges in its temperature.

Consequently, all forces acting on base member 61 due to vibration andshock are transmitted directly from and to the case or frame by springs66, 67 and 69, permitting no change in their relative positions exceptfor longitudinal expansion of base member 6. Channel member 76, which isthe supporting frame and point of reference corresponding to part inFIGS. l2 to 16 inclusive, is equally rigidly supported. Both must havesuicient resistance to bending or torsional strain not to be resonantbelow 2000 c.p.s. in the direction of the X or Z axis.

All parts of the operating structure being made of the same material asactuating member 61, or else of materials with the same coecient ofthermal expansion, a change in ambient temperature will not causerelative motion between contacts 87 and 89. This is true irrespective ofthe material used to provide the casing. Not only must this expansionmember and the channel element 64, or its equivalent, be made of thesame metal, but also springs such as 67 and 69, as well as bracket 71B,should be made of the same material. Even the coeflicient of expansionof pins 73, 81 and 82 is of importance, This is true because anydifference in their expansion in comparison with spring 67 and bracket70 is multiplied by the action of the V spring assembly S8. The entirerelay may be mounted on a suitable supporting surface, conveniently bythe use of the extensions or foot portions 60. The relay is especiallyuseful in connection with a printed circuit defined on one side of aninsulated panel, which latter mounts the relay upon its opposite face.Pins 63 and 94 are, of course, extensible through such a panel forconnection to the circuit defined thereon.

In the structures so far reviewed the relay in each instance hasincluded contacts normally spaced from each other so as to provide anopen circuit. It is obvious that while following the same teachings, itis entirely feasible to furnish a relay in which the contacts arenormally engaged, so that the circuit is closed. However, these contactswill sepa-rate after the expiration of a desired time interval. In thisconnection, attention is invited to FIGS. l0 and 11, in which numeralssuch as 61, 64, 73-75, S2, 85 and 93 have been employed to `designateparts substantially identical with those heretofore designated by thosenumerals. In this view the frame member 76 also corresponds generally tothe member 76 as heretofore described. However, strip 97, correspondingto strip 86, mounts in FIGS. l0 and 11 a U-shaped bracket 98. To theinner face of the base of this bracket there is secured a contact 99. Acooper-ating Contact 100 is carried by a spring strip 101, which has itsinner end suit-ably secured to bracket 85. Bracket 8S also moun-ts theupper arm of a V-shaped spring assembly 102 corresponding to theassembly 83. That strip may also supporta small V-shaped piece 102corresponding in structure and function to piece 88 previouslydescribed. The lower arm of assembly 162 is attached to pin 73. Abearing member 103, preferably presenting a convex contact surface, ismounted by spring 101 to extend from its side face in a directionopposite to that of contact 100. This bearing member engages with theface of spring assembly 102.

It is obvious that in this form of structure, spring assembly 102 servesonly the function of pushing the movable contact 160 in an upwarddirection, or else of permitting that contact to be lowered. In thisconnection it will be appreciated that spring strip 101 normally urgesthe contact in the latter direction. Screw 93 is adjusted so thatcontact 99 exerts a certain pressure on contact 100 and spring assembly162 when the relay is not energized. This pressure causes a definitedeection at the tip of the spring assembly 102 from its free position.Therefore, elastic stresses are set up in the structure. When power isnow applied to the heater of the actuating member, the initial expansionof the latter gradually neutralizes these stresses until they areeliminated. Thereafter, the contacts 92 and 100 separate.

To modify the structures shown in FIGS. l to 1l inclusive in accordancewith FIG. 16, it is necessary only to substitute a suitably externallyheated ribbon for the base or actuating member of the motion-multiplyingmechanism as disclosed, for example, in FIGS. 7 to 10 of my priorapplication for United States patent on Electrical Control Device led onMarch 13, 1958 under Serial No. 722,364. Otherwise, the assembly shouldpreferably follow generally an arrangement of mechanism as heretoforedisclosed, in which the first motion-multiplying mechanism will involvea base in the form of an actuating member connected to the outer orcompensating member in a manner such that movement of the base incidentto expansion of the latter will cause a magnied movement on the part ofthe outer member. The second motion-multiplying mechanism is arrangedserially, or in cascade relationship, with the first mechanism by havingits operating part connected to the pin 73, or its equivalent, throughsuitably coupling the free arm of the spring assembly 88 to that pin.Therefore, the actuating part of the second mechanism, which is adjacentthe apex of the spring assembly, will have a magnied or multipliedmovement with respect to the adjacent contact, in View of the fact thatthe second arm of the spring assembly is connected to what might betermed a base provided by bracket 85. Additionally, one or two flat leafsprings may be attached to the back of channel 76 adjacent its ends andbearing with their free ends with substantial pressure againstcompensating member 64 adjacent its center. This will place theactuating member under continuous tension, as heretofore described.Another at leaf spring may be attached to the inside of casing 5S andmade to bear with light tension with its free end against the centralportion of the actuating member to suppress resonant vibration, also aspreviously described.

From the foregoing, it is apparent that a relay assembly is furnishedwhich avoids the diificulties inherent in certain structures, aspreviously outlined. Preferably a closed structure is furnished, and theuse of cantilevers is minimized. The weight of moving parts decreasesrapidly as the motion is multiplied. This decrease is far more rapidthan inversely proportional to the ratio of multiplication. Themotion-multiplying mechanisms are arranged in cascade, with their axesof maximum shock and vibration sensitivity at right angles to eachother. The damping of vibration is achieved, and the biasing and dampingfunctions are separated, by using different springs for each purpose.Thermal convection currents are blocked. The Weight of the outermostmotion-multiplying assembly is only a fraction of that of the base oractuating mechanism, so that a properly tapered design is achieved.

Thus, among others, the several objects of the invention as specificallyaforenoted are achieved. Obviously, numerous changes in construction andrearrangements of the parts might be resorted to without departing fromthe spirit of the invention as defined in the claims.

I claim:

1. A relay including in combination a base, means for heating said base"tr'c'se expansion of the same, a mechanism operatively connected to Saidbase whereby parts of said mechanism will have movements greater 1l thanthe expansive movements of said base, a pair of cooperatingcircuit-controlling contacts, one of said contacts being connected formovement with said mechanism parts, said one contact being Subject tovibration transmitted to said relay from a source exteriorly of thesame, the connection between said one contact and mechanism parts`comprising a furtherV motion-multiplying mechanism and means yieldinglybearing and frictionally rubbing against said further mechanism, thusdamping vibratory movements of said one contact.

2. A relay including in combination a base, means for heating said baseto cause expansion of the same, a mechanism operatively connected toSaid base whereby parts of said mechanism will have movements greaterthan the expansive movements of said base, a pair of cooperatingcircuit-controlling contacts, one of said contacts being connected formovement with said mechanism parts, a compensating member forming a partof said mechanism for preventing movements of the parts of the latterand said contact when said base expands and contracts due to ambienttemperature changes, a shell enclosing said base and said mechanism, anda shield supported within said shell at a point between and spaced fromsaid base and compensating member, said shield substantially dividingthe space within said shell into two compartments to the extent that thethermal linkage by convection currents between Said base and saidcompensating member is reduced, even under high unidirectionalacceleration of the relay as an entirely, to a magnitude which is smallcompared to their linkage by thermal conduction and radiation.

3. In a relay as dened in claim 2, said shield extending from a pointadjacent one inner face of said shell to an opposed face thereof. l 4. Arelay including in combination a motion-multiplying mechanism comprisingan expansible and contractable base, an outer member and means forconnecting Said outer member to said base whereby in response toexpansive movement of the latter said outer member will have magnifiedmovement, a second motion-multiplying mechanism, an actuating part insuch second mechanism connected to said outer member, an operating partalso in said second mechanism, a pair of relatively movable contacts,one of which is connected to said actuating part to be moved thereby,heater means cocacting with the base member of said first mechanism forcausing expansive movements on the part of such member, a supportingstructure, means for Securing the base of said first mechanism againstmovements with respect to said structure in a zone adjacent one of itsends, the opposite end of said base being movable with respect to saidsupporting structure, and a link interposed between said supportingstructure and said last-named end of said base to provide a pivotalconnection between the parts.

5.r A relay including in combination a base, means for heating said baseto cause expansion of the same, a mechanism operatively connected tosaid base whereby parts of said mechanism will have movements greaterthan the expansive movements of said base, a pair'of cooperatingcircuit-controlling contacts, one of said contacts being connected formovement with said mechanism parts, said one contact being subject tovibration transmitted to said relay from a source exteriorly of thesame, means for damping vibration of said one contact, biasing meanscooperating with said mechanism parts for exerting tension on said base,said damping and said biasing means comprising separate springsthrusting against different points of said mechanism parts, and meansfor mounting said springs independently of Said parts and said base.

6. A relay including in combination a primary mononmultiplying mechanismembracing an expansible base and a pair of inflexible arms movablyconnected to said base at spaced points and to each other to provide anapex portion, heating means acting upon said base to cause expandingmovement of the latter and magnified movement of said portion, a secondmotion-multiplying mechanism embracing a pair of relatively movable armsconnected to each other, to a support providing a point of reference andto the apex portion of the first mechanism, the arms of the secondmechanism providing an apex portion having magnified movement incomparison with that of the apex portion of the first mechanism, a pairof cooperable circuit-closing contacts, means for mounting one of thesame adjacent the other and the other contact of said pair beingconnected for movement with the apex portion of the second mechanism.

7. In a relay as defined in claim 6, the apex portion of said firstmechanism moving in a given direction, and the apex portion of thesecond mechanism moving in a direction substantially at right angles tothe movement of the first apex portion.

8. A relay including in combination a multi-part mechanism comprising abase formed of thermally expansible material, arms connected at spacedpoints to said base and to each other to provide an apex portion, meansadjacent said base to heat and expand the same, the arms causing saidapex portion to have a greater range of movement than the expansivemovement of the base as it is heated, a second multi-part mechanismconnected to said apex portion and having an area shiftable through agreater range of movement than said apex portion as said base is heated,a pair of cooperating contacts, one of said contacts being mounted bysaid area and the mass of the second mechanism being a fraction of themass of the first mechanism.

9. In a relay as defined in claim 8, said first mechanism beingsubstantially rigid, the expansion and contraction of said base beingmultiplied through to said area of the second mechanism and the mass ofthe mechanisms changing at least as rapidly as inversely proportional tothe ratio of multiplication.

l0. In a relay as defined in claim 8, a casing enclosing said mechanismsand contacts and means supporting said mechanisms and contacts at aplurality of points within said casing, said supporting means beingyielding at no-t less than all but one of said points.

11. A relay including in combination a base of thermally expansiblematerial, means adjacent said base to heat and expand the same, bracketsat opposite ends of said base and rockingly connected thereto, a memberextending between said brackets and having its ends rigidly connectedone to each of the same, said member having a Zone of iiexureintermediate its ends, a second member connected to said first member toextend in parallel and spaced relationship thereto, a V-shaped springstrip having one of its legs connected adjacent the zone of fiexure ofsaid first member to move therewith, its other leg being substantiallyfixed, a first contact supported against substantial movement withrespect to said second member and a second contact supported formovement with said strip to cooperate with said first contact.

12. In a relay as defined in claim l1, spring means frictionally andslidably bearing against said strip to damp vibrations of the same.

13. In a relay as defined in claim 11, said second contact being securedto said strip adjacent its arch portion, and means for adjusting saidcontacts toward and away from each other.

supporting said first contact, and means carried by said second memberand movably bearing against said bracket for adjusting the position ofthe former.

16. A time-delay relay comprising an element longitudinally expansibleby heat, a portion of said element constituting a point `of reference;means adjacent said element to heat and expand the same, a iirst motionmultiplier including two joined arms in mutually similar conditions oflongitudinal stress operatively connected between the extremities, andmotionally responsive at their junction to the length, of said element;a second motion multiplier including two joined arms in mutually`opposite conditions of longitudinal stress operatively connectedbetween said junction and a point whose position relative to said pointof reference is at least substantially fixed; and circuit control meansresponsive to the movement of the junction of the arms of said secondmotion multiplier.

17. ln a relay as defined in claim 16, said circuit control meanscomprising a pair of contacts, `one of said contacts being connected formovement with said second motion multiplier to engage and separate fromthe second of said contacts and means yieldingly bearing andfrictionally rubbing against a part adjacent said one contact to thusdamp vibratory movements thereof.

18. A time-delay relay comprising in combination a iirst structurebowable toward and away from a plane containing its extremities to adegree responsive to the separation between these extremities; a secondstructure operatively connected between an intermediate point on saidiirst structure and a nearby point in said device which is displacedfrom the line defining the locus of movement of said inst-mentionedpoint, said second structure having a portion extending in a directionat least principally normal to said plane to, and including a region at,a distance from said iirst-mentioned point large compared with theseparation between said points; means forming a part of said rststructure for rendering the separation between the extremities of saidrst structure dependent on temperature variations, means for creatingsuch variations and switch means connected to respond to the movement ofsaid region occurring in the plane defined by that region and saidpoints.

19. A time-delay relay comprising in combination a rst structure bowabletoward and away from a plane containing its extremities to a degreeresponsive to the separation between those extremities; a relativelysharply V-shaped structure having its axis disposed in a direction atleast principally normal to said plane, having one outer extremityoperatively connected to an intermediate point on said iirst structure,and having its other outer extremity connected to a nearby point in saiddevice; means forming a part of said -first structure for rendering the`separation between the extremities of said rst structure dependent ontemperature variations, means for creating such variations and switchmeans connected to respond to the movement of the apex of said V-shapedstructure occurring in the plane defined by that structure.

20. A time-delay relay comprising in combination an elementlongitudinally expansible by heat, means for creating heat to expandsaid element; a lirst motion multiplier, including two arms joinedtogether in serial relationship, operatively connected between theextremities, and motionally responsive at the junction of said arms tothe length, of said element; a second motion multiplier, including twoarms joined together in serial relationship, operatively connectedbetween said junction and another point in said device, the two arms ofone of said multipliers being in mutually similar conditions of stress,and

14 the two arms of the other of said multipliers being one in tensionand the other in compression; and switch means connected to respond to`the movement of the junction of the arms of the second motionmultiplier.

21. A time-delay relay comprising in combination an elementlongitudinally expansible by heat, means for creating heat to expandsaid element; a first motion multiplier, including two arms joinedtogether in serial relationship, operatively connected between theextremities, and motionally responsive at :the junction of said arms tothe length, of said element; a second motion multiplier, including twoarms joined together in serial relationship, operatively connectedbetween said junction and another point in said device, said secondmotion multiplier being disposed along a plane generally normal to thatalong which said iirst multiplier is disposed; and switch meansconnected to respond to the movement of the junction of the arms of thesecond motion multiplier occurring in 4the plane along which said secondmultiplier is disposed.

22. A time-delay relay comprising in combination an elementlongitudinally expansible by heat, means for creating heat to expandsaid element; a structure connected between the extremities of saidelement and bowable toward and away from said element to a degreeresponsive to the separation between those extremities; a motionmultiplier, including two arms joined together in serial relationship,operatively connected between an intermediate point on said structureand another point in said device, said motion multiplier being disposedalong a plane generally normal to that along which said element andstructure are disposed; and switch means connected to respond to themovement of the junction of the arms of said motion multiplier occurringin the plane along which said multiplier is disposed.

23. A time-delay relay comprising in combination three arms joined in aclosed loop, one of said arms being longitudinally expansible by heat,means for creating heat to expand said one arm whereby to move one ofthe points of juncture relative to the arm opposite that point; a motionmultiplier, including two arms joined together in serial relationship,operatively connected between said point of juncture and another pointin said device, said motion multiplier being disposed along a planegenerally normal to that along which said loop is disposed; and switchmeans connected to respond to the movement of the junction of the armsof said motion multiplier occurring in the plane along which saidmultiplier is disposed.

References Cited in the le of this patent UNITED STATES PATENTS1,864,049 Mulvany June 21, 1932 2,265,486 Judson Dec. 9, 1941 2,611,855Turner Sept. 23, 1952 2,660,646 Fritzinger Nov. 24, 1953 2,664,483Broekhuysen Dec. 29, 1953 2,700,084 Broekhuysen Jan. 18, 1955 2,777,969Svensson Jan. 15, 1957 2,798,134 Geer July 2, 1957 2,917,932 Kline Dec.22, 1959 FOREIGN PATENTS 20,085 Great Britain Sept. 5, 1913 651,151Great Britain Mar. 14, 1951

